Armature for small electric motors



Oct. 26, 1937.

F. SCH-NEIDER 2,097,134

ARMATURE FOR SMALL ELECTRIC MOTORS Filed D90. 28, 1935 Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to armatures for small electric motors, and more particularly to armatures provided with shoes mounted detachably on the armature-cores for the purpose of permitting completely wound coil-bodies to be placed onto said cores. As compared with a known construction of this kind in which the armaturecores can be separated from the hub of the armature, according to this invention there is provided a construction having an increased magnetic. effect, and in addition, providing a greater space for the reception of the wire-coils. In known armatures for small electric motors a proper connection between the armature-cores and the hub can only be attained with cores constructed detachably from said hub, if the diameter of the latter is at least so dimensioned that slots of greatest possible depth are available on the armature-cores, because otherwise the latter owing to the weight of the wire-coils and the armature-shoes imposed thereon are liable to be loosened in their seat upon the armature. It is also necessary in this case to embed .the armature-cores at a relatively great depth in the hub, in order to prevent an excessive resistance being presented to the magnetic flux when passing through the armature; By reason of this, the hub of the armature will occupy an excessive space, as compared with the total diameter of the armature, so that coils with only a relatively small number of turns of wire can be mounted on said core, thus reducing the electromagnetic efiect exerted by said coils upon said cores.

These disadvantages are successfully avoided with an armature constructed according to the invention. According to this invention, in the first place the armature-cores are constructed to form a whole with the hub, that is, said core is made integral with said hub so that no impediment is presented to the passage of the magnetic flux through the armature. In the second place, a hub constructed in accordance with this invention may be made of relatively small diameter without impairing the mechanical strength and ruggedness at the places at which it is joined to the armature-cores. Finally, in a construction according to my invention, larger Wire-coils may be used on the armature-cores for the magnetization thereof, this being due to the fact that the space between the hub and the shoes with a given diameter of the armature, can be made appropriately larger with the result that it may be more fully utilized. The number of ampere- 55 turns in the magnetizing coils on the armaturecores may therefore be appropriately increased, thus improving the magnetizing efiect of said coils, which is especially desirable for small electric motors.

In the accompanying drawing, which forms part of this specification, a construction of an armature according to the present invention is shown in which Fig. 1 is a side-view of a complete small electric motor equipped with the novel armature, Fig. 2 a side-view of the novel armature-core constructed integral with the hub, the armature being composed of three cores in starshaped arrangement, Fig. 3 a View on Fig. 2 taken perpendicularly thereto, Fig. 4 a longitudinal section through one of the armatureshoes constructed detachable from the respective armature-core, Fig. 5 a plan-view and Fig. 6 a side-view of the armature-shoe shown in Fig. 4, Fig. 7 a front-and side-view of a locking-disk destined to be placed onto the free end of each armature-core for fastening thereto the respective armature-shoe, Fig. 8 a section through an armature-core with an armature-shoe mounted thereon together with locking-disks as shown in Fig. '7, securing proper connection therebetween, Fig. 9 a top-view showing an armature-shoe 'together with locking-disks securing the former to the free ends of the armature-core, and Fig. 10 a view of a coil-body adapted to be placed onto the armature-core.

Referring more particularly to the drawing, the three armature-cores a of the construction shown herein are integral with the hub b and provided, as shown particularly in Figs. 2 and 3, at their free ends on both sides thereof with an incision or notch c and with a longitudinal recess d at the projecting edges of each of said cores. In this manner, there will be provided open locking-noses e as clearly shown in Fig. 3, said noses serving for fastening an armatureshoe f to each of the armature-cores a. The shoes 1 are provided at their under side with a recess g made by milling, said recess permitting passage of said locking-noses e therethrough only in upward direction and being of rectangular form corresponding to the cross-section of the armature-cores a. The recess 9 extends along the greater part of the edges of each armatureshoe f. Each armature-shoe f is further provided on the opposite side thereof, with circular recesses h and h which may be made by milling, said recesses 71. and h being positioned at a distance from each other in the center-line of said shoe and passing not entirely therethrough. The distance between said recesses h and h is in a a proper space for the reception of suitable locking-members. These locking-members consist of disks 7c of wedge-shaped cross-section fitting into the recesses h and h said'disks, 70 being providedwith a marginal incision 1 permitting passage of the locking-noses e on the, cores a and in addition to this, with the sockets m adapted to be engaged by a socket-wrench. As shown in'Fig. 10, the coil-bodies n which serve for the reception of the windings are made of rectangular form of a cross-section corresponding to that of the armature-cores a.

Assembling of the aforedescribed armature is accomplished as follows: The coil-bodies n with the windings thereon, are placed one upon each of the armature-cores a being passed over the free ends of the latter. The shoes 1 are then mounted upon said cores a in such a manner that theinterior recess 9 on each shoe ,1 grips over the free end of therespective core, so that the latter will be embedded in the said recess. During mounting said shoe f on said core a. care must be taken that the marginal incisions i and in the circular recesses h and h will be in position to register with the complementary locking-noses e on the free'ends of the cores a, if said shoes are being pressed upon their seatingsurface at the free ends of said cores. The locking-noses e thus pass through the marginal incisions i and i on the margins of the circular recesses h and h respectively and the longitudinal recess g on the inner surface of the shoe will engage the free end of the core in such a manher that the shoe will be secured on said core against longitudinal and transverse displacement. In order to secure the shoes against being taken off said cores in radial direction, the locking-disks k are placed in the circular recesses'h and h on the-shoes f, the marginal incisions i and i now overlapping the locking-noses e on the free ends of the cores a and being secured by the aid of a suitable wrench having projections fitting into the sockets m on the locking-disk 7c. Upon r0- tation of the locking-disk k, the thinner portions of the disks will firsticome underneath the locking-noses e, and upon further rotation of said disks gradually the thicker parts of Wedgeshaped conformation will come under said noses e, said latter parts acting like wedges during in creasing tightening. The shoes I will thus be securely kept in position on the free ends of the cores a. If it becomes necessary or desirable to disassemble the armature, the locking disks "7c are rotated in a reverse direction by means of the Wrench, so that said disks, together with the shoe, may be removed from the core a.

I claim:

1. Armature for small electric motors, said armature comprising a hub, a plurality of armature-cores extending in radial direction from said (hub and being integral with the latter, a coilbody in completely wound condition mounted on each of said cores, a shoe detachably fastened to the free ends of each of said cores, lockingnoses on said free ends of said cores, openings on said shoes permitting said noses to pass therethrough, a recess on the under side of said shoe,

said recess permitting reception of the free end of a core, and two further recesses on the upper side of each of said cores, said latter recesses adapted for the reception of means for securing said shoes to said cores.

2. Armature for small electric motors, said armaturecomprising a hub, a plurality of radially extending armature-cores integral with said hub, a coil-body mounted on each of said cores, a shoe detachably mounted on the free end of each of said cores, locln'ng-noses on the free ends of said cores, openings on said shoes, said openings permitting reception of said locking-noses, a recess on the under side of said shoe, said recess permitting reception of the free end of a core, and two further recesses near the outer edge of each of said cores, each of said latter recesses being adapted for the reception of a rotatable disk of wedge-shaped cross-section having a marginal incision permitting passage of one of said locking-noseasaid disks being mounted rotatably within each of said latter recesses, so that the former will grip underneath 'said noses with. its marginal parts of full thickness.

3. Armature for small electric motors, as specified by claim 2, in which said locking-disks are provided with sockets adapted for the reception of a Wrench. 7

4. An armature for small electric motors comprising, a hub having a plurality of armature cores extending radially therefrom and formed integrally therewith, each of said cores having a notch near its free end, a shoe for each of said cores, each shoe having a mortise slot to receive the free end portionof its associated core, and being provided with a recess intersecting said slot, and a notched disk in said recess engaging in said notch in said core for detachably securing the shoe to the core.

FERDINAND SCHNEIDER. 

